The company said $100,000 (£77,000) was spent on about 3,000 ads over a two-year period, ending in May 2017.
The ads did not back any political figures specifically, but instead posted on topics including immigration, race and equal rights.
Facebook said it was co-operating with a US investigation into the matter.
The advertisements directed users towards around 470 accounts that spread false information or were otherwise in breach of Facebook’s terms and conditions, the site said.
